2. Field of the Invention
This invention relates to a new taker gripper which, by using two weft gripping and clamping members arranged in series, one of which is of elastic type and the other of wedge type, is particularly suitable for transporting multifilaments, flat wefts, large-section monofilaments or several wefts to be inserted simultaneously.
2. Description of the Prior Art
In the state of the art various types of taker grippers using different weft gripping and clamping members are already known, their efficiency being knowingly one of the most difficult problems to be solved in the field of high-speed shuttleless looms, the difficulty deriving from the contrasting technical requirements of securely clamping the weft yarn so that during transport it is not lost by virtue of the pulling, vibration or intense acceleration always present in such looms, while at the same time softly gripping and transferring said weft yarn so as not to damage it, in that it does not generally possess very high strength.
In one known type of taker gripper the gripping and clamping member consists of the end of a lever pressed by a spring against a corresponding weft gripping surface provided on the gripper body. Such a member, although perfectly satisfying the gripping requirements for multifilaments, flat wefts, large-section monofilaments and several wefts to be inserted simultaneously, is however only able to effect "positive" gripping, which means that during weft yarn reception or release it has to be opened by a further appropriate external control device, this involving a series of considerable problems due substantially to the great difficulty of phasing the gripping and clamping member with said external control device because of the high speed of the loom and in particular because of the inevitable slack which arises between the various mechanical members.
In other known types of taker grippers the gripping and clamping member is of the "negative" gripping type, and consists substantially of a wedge axially movable within a hook in the gripper body, against which it is pressed by a spring, said hook and said wedge being shaped to form between them, on one side, a narrow V recess into which the weft is inserted to remain securely trapped.
These latter gripping and clamping members obviate the said drawbacks of positive gripping, but suffer from the problem of not achieving effective and reliable gripping in the case of multifilament wefts, of flat wefts, of large-section monofilaments or of several wefts to be inserted simultaneously, in that there is only one weft yarn clamping point within said V recess between the wedge and the hook, so that this can only retain the first filament inserted into said V recess, while any other filaments remain poorly clamped or even free. Again, if flat wefts or large-section monofilaments are present a single gripping point is insufficient to ensure effective and reliable clamping because the rigidity of said wefts tends to release them by making them rotate about their gripping point until they escape from the V recess.